Third-rail insulator.



i 10.723,062. f PATRNTRD MAR. 17, 1903.

A s. B. STEWART,l JR.

THIRD RAIL INsULAToR.

APPLICATION FILED SEPT. 29 1900.

N0. MODEL.

UNITED STATES y ATENT f Prion.

SAMUEL B. STEWART, JR., OF SCHENECTADY, NEW YORK, ASSIGNOR TO `GENERALELECTRIC COMPANY, CORPORATION OF NEW YORK.

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SPECIFICATION forming pare of Letters Patent No. 723,062. dated March17, 1903 Application led September 29, 1900. Serial No. 31,511. (NomodeLl To @ZZ whom itnmay concern: v

Be it known that I, SAMUEL B. STEWART, Jr., a citizen of the UnitedStates, residingat Schenectady, in the county of Schenectady, State ofNew York, have invented certain new and useful Improvements inThird-Rail Insulators, (Case No. 1,40S,) of which the following is aspecification.

This invention relates to improvements in zo insulating-supports for thepower-conductor rails of electric railways, which are popularly calledthird rails, being usually ofthe same type as the track-rails.Insulators of this type hit-herto in use have been satisfactory I5 withrespect to theirinsulating qualities; but owing to their structure theyhave not had suflcient mechanical strength to withstand the strains towhich they aresubjected bythe y expansion and contraction of therailsand by zo vertical movements of the ties on which they are usuallymounted, which movements are caused by passing trains. The problempresented by the expansion and contraction of the rails is the mostserious with which the `makers of third-rail insulators have to contend,the variation in length of a section of five hundred feet, for example,1being Vfrequently three inches or more.

Insulators hitherto in use have been pro` 3o vided on opposite sides oftheirA upper portions or rail-supports with ears or lugs-which tightlygrip and securelywhold the base of the conductor-rail. Each ofthese earsis in cer-` tain types cut away at one corner,iso that when the support.is turned at an angle to the rails the rail can be inserted upon thetop of the support, and when the'latterzis moved back in line with therails the rail 'will be sey curely gripped and held beneath the ears.

4o Although the ears have been formed integral with a malleable-ironsupport, they are frequently broken off, and in such case not only isthel usefulness" of the insulator `at an end,

but the rail itself will slip off from one side of the top of the support, andlthedownwardlyspring-pressed collector-shoe 'carried by the`car will be forced against the free abutting A end of the next rail andwrecked. If the ears fail to break, the rail will either pull the in- 5osulator from the ties or break it, in any case causing the displacementof the rail from the path of the collecting-shoe. As the greater effectof the expansion and contraction of the rails is longitudinal, it mightreasonably be supposed, since the ears do not hold the rail fromlongitudinal movement, that the rail could move longitudinally betweenthe ears without affecting them. This, however, is not the case, as inpractice it has been found -that the reason that the ears have beenbroken 6o off is because the insulator had been tipped in the runningdirection of the rail. This action was caused by the sticking of thefoot of the rail to the top of.' the iron rail-support of the insulator,which was in turn caused by 65 the formation of rust-scales between therail and the support, which substantially welded the two together'.

As has been stated above, the insulators `are` usuallymounted on thesame ties toA 7o which the trafticrails are secured, and therefore whenthe car or train is passing the ties and insulators are depressed, thuspulling the ears against the foot of the rigid rail, causing them to bebroken off. proposed to make the insulator in two relatively movableparts, one to be secured to the tie and the other adapted to retain thecond uctor-rail tightly beneath the ears, thus permitting the lowerportion to move with 8o the ties at the time of the passage of a trainthereover without aecting the `upper portion, which retains the foot ofthe rail.

It is evident that if the base of the rail and the top of the insulatorare stuck together by` 85 rust, so that by expansion and contraction andby the ,action of the collector-shoe the insulator is tilted, the partsof such an insulator will be held tightly together by the clampingaction of the rail, so that the latter 9o will have absolutely no freemovement at the time of the passage of a train and the ears be brokenoff just as if the insulator had been made in one insteadof` two'-pieces.

The above-described difcultiesha've been 95 a serious annoyance torailroad managers for some time, and competent engineers have ybeen ataloss for a solution of the problem presented.

Insulating-supports constructed in accordloo ance with this inventionare no more difficult or costly' to make than those hitherto in use,

It has been 4 of malleable iron, to make a tight tit.

but they overcome all the defects in the latter which have provedserious in practice.

The invention consists in providing means for insuring free movement ofthe conductorrail through the top of the insulating-support and is notlimited vto details of structure.

Of the drawings, Figure 1 is an end elevation of an insulatorconstructed in accordance with my invention, showing also in section aportion ot' a conductor-rail in position upon the top of the support ofthe insulator. Fig. 2 is a lateral elevation of the same, the rail beingremoved; and Fig. 3 is a plan according to Fig. 1, but with the railremoved.

The angular insulating-base B of the support'ismade of suitable wood,such as ash, which is prepared and japanned to increase its insulatingproperties. A metal band 4 surrounds its lower part to prevent splittingor spreading by the bolts by which it is secured to a tie, which boltsextend through incisions 5 on opposite sides of the base, whichincisions are oppositely inclined in the direction of motion of thetrain and collectorshoes carried thereby. The base B is cut away, asshown at 3 and 2, to increase the moisturecreeping surface, and over itsupper portion is jammed the support S, preferably formed The lower edgeof the support S is formed with a petticoat for shedding moisture andwhich also increases the internal creeping surface. Integral projectionsor ridges A are formed on the top of the support S, and they are curvedlongitudinally and laterally, so that 'a very small portion of theirsurface is in contact with rail R, whose foot F rests upon the ridges,so that the rail when caused to be tilted, as described above, can rocklongitudinally or laterally. Since the very small surface of theseridges is in Contact with and carries the Weight of the conductor-railand the ridges form a space between the rail and support, therust-scales which form in the top of the support S and the bottom of therail-base F are powerless to cause a union or weld of the support andrail. This space also prevents the lodgment of water between the railand the support and offers free access to air-currents, which willevaporate any Water whichmight temporarily lodge in the space. Thelatter is thus free at all times to move longitudinally between the earsand Without tilting the support, so that the ears will not be broken.Integral ears E also extend upwardly from diagonally opposite corners ofthe top of the support S, their office being to prevent the rail frommoving laterally from oit the support and from being removed verticallyfrom the support when the latter is fixed in the Aroad-bed. A sufficientdistance exists between the inner surfaces of the ears and the top ofthe support to provide room for the free movement of the base of therail when it is rocked longitudinally or laterally. This space alsoserves to provide limited free vertical movement of the supportindependently of the conductor-rail when the tie on which the support ismounted is depressed by a passing train. As shown in Fig. 3, each ear iscut away to permit the insertion of the railbase beneath the ears.

The support S is rigidly mounted upon the square wooden base B at thefactory. When the device is to be used, it is turned at an angle to theroad-bed, so that the lines 6 6 are parallel with the desired line ofrails. The rail-base may then be readily inserted upon the ridges A, andthen the entire device is turned so that the ridges A are parallel tothe rail, and finally bolts are inserted through the openings 5 and aresecured in the tie.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

l. A rail-insulator support which is provided with ears for holding therail upon its top, and means for insuring free longitudinal andyvertical movements of the rail between the ears.

2. A rail-insulator support which is provided with means for forming aspace between the proximate surfaces of the rail and support, to preventtheir sticking together by rust.

3. A rail-insulator support which is provided with integral projectionsof relatively small surface, upon which the rail rests.

4. A third-rail insulator comprising an insulating-body adapted to bemounted on the ties or sleepers to which the track-rails are secured andarail-support rigidly carried thereby, the said support being providedwith ears which in the operative position of the support overhang theflange of the rail but are separated from the top of the support andfrom the flange of the rail by an amount sufficient to permit a freevertical movement between the rail and the support so that when apassing train depresses the ties the support may also be depressedwithout causing a relative movement between the support and theinsulating-body on which it is mounted.

5. A rail-insulator support which is provided with projections ofrelatively small surface, which projections are higher at thelongitudinal center of the support to permit the rail to rocklongitudinally.

6. A rail-insulator support which is provided with projections ofrelatively small surface, and higher at certain transverse points thanothers, to permit the rail to rock transversely.

7. A rail-insulator support which is provided with projections ofrelatively small surface, higher at the longitudinal center of thesupport, and higher at certain transverse points than at others topermit the rail to rock longitudinally and transversely.

8. A rail-insulator support which is provided with a longitudinal ridgewhich is curved transversely and longitudinally.

9. A rail-insulator support which is provided with projections ofrelatively small surface, and higher at some points than at others,

IOO

IIO

l to permit the rail to be rocked or tilted, and

is also provided with ears which in the operative position of thesupport prevent the removal of the rail therefrom, but which havesufficient space between them and the top of the support to allow freerelative movement of the rail and the support.

10. A rail-insulator support of malleable iron, which has integralprojections of relatively small surface, and integral ears for retainingthe rail, which allowa limited relative movement of the rail andsupport.

11. A third-rail insulator1 comprising an insulating-body'adapted to bemounted on the ties or sleepers to which the traffic-rails are securedand a third-rail support rigidly mounted thereon, thesaid support beingprovided with ears rigid with the support which in the operativeposition of the support overhang the ange of the rail but are separatedfrom the top of the support and from the flange of the rail by an amountsufficient to permit a free vertical movement between the rail and thesupport so that when a passing train depresses the ties the support maybe depressed. without causing a relative movement between the supportand the insulating-body on which it is mounted.

12. A railinsulator support provided with ears which in the operativeposition of the support overhang the iiange of the rail and prevent theremoval of the rail laterally or vertically therefrom, the said earsbeing separated from the top of the support and from the flange of therail by an amount suicient to permit a free relative movement of therail andthe support on the passage of atrain, and projections ofrelatively small surface between the proximate surfaces of the rail andsupport.

13. An insulated support for conductingrails which is provided'withmeans for forming a space between the rail and the support,

whereby rust-scales are prevented from forming to cause the rail tostick to the support.

14. The combination with a base, of a railsupport rigidly mountedthereon, insulating material between the support and the base, and lugsor ears on the said support, the said ears being arranged to overhangthe flange of the rail in the operative position of the support andbeing separated from the top of the support and the iange of the rail byan amount sufcient to permit a free Avertical movement between the railand the support on the passage of a train.

15. In a third-rail insulator, the combination with the insulating-body,of a third-rail support rigidly carried thereby, and means combined withthe support to normally hold the third rail from lateral and verticalremoval, but also to permit the support to be depressed independently ofthe rail..

. In witness whereof I have hereunto set my hand this 26th day ofSeptember, 1900.

SAMUEL B. STEWART, JR.

Witnesses:

' BENJAMIN B. HULL,

GENEVIEVE HAYNEs.

